    Patent document 1: JP-2005-3431 A    Patent document 2: JP-2002-286479 A
Patent document 1 discloses a map display apparatus to acquire telephone book data from a storage medium of a cellular phone using a communication function of the cellular phone. The telephone book data has individual information including a name, address, and telephone number. The apparatus then specifies spot coordinates based on the address or telephone number included in the individual information to thereby display contents of the individual information on a position on a map (also referred to an on-map position) corresponding to the specified spot coordinates.
Patent document 2 discloses a map display apparatus having: a storage medium storing map data in which place names, telephone numbers, and addresses in association with coordinates data; and a communication device communicating with an external database for storing map data. When the data corresponding to destination information is not stored in the internal storage medium, the apparatus acquires coordinates data corresponding to the destination information from the external database using the communication device to thereby specify a destination. Thus, a destination can be specified even without a new place name or a new telephone number being internally stored in the storage medium.
The apparatus in Patent document 1 specifies a spot coordinates based on the address or telephone number to thereby display the content of the individual information on the position on the map corresponding to the specified spot coordinates. Such individual information may include address information, which does not contain an upper layered information item such as a prefecture or a city. The apparatus may therefore specify a spot coordinates, which has the same place name but is completely different from the targeted one to thereby cause a problem that the contents of the individual information is displayed in a wrong position.
That is, when a spot is retrieved by using a name, address, or telephone number as a retrieval condition and the retrieved spot is directly displayed on a map, a problem may occur that the accurate spot is not displayed.
Further, the apparatus in Patent document 2 acquires the coordinates data corresponding to the destination information from an external database and specifies a position corresponding to the coordinates data as a destination. Therefore, there may be a difference between internal map data stored in the storage medium and external map data stored in the external database. When the coordinates data acquired from the external database has a displacement, a problem may occur that the destination is displayed in a position displaced from the proper one.